This chapter provides relevant information on the background to the research project carried out by the Author and the reasons for integrating Plain English into the PhD programme at Bialystok University of Technology. The chapter proceeds with a description of the aims of the multiple-case study on the improvement of the writing skills of 13 Polish doctoral students from BUT and presents four research questions operationalised by a total of nine hypotheses. The subsequent sections are concerned with the study’s conceptual framework and design, a full picture of the study participants, the instructional tools applied in the didactic intervention and the data elicitation instruments. The chapter closes with a short section on data analysis.